This hack prevents the perm_invent window for X11 on OSX from
creeping every time it gets updated. It is far from perfect and
at the very least ought be handled via user settable X resources
rather than hardcoded values, but it's as much effort as I'm likely
to spend.
Add a new file containing a list of issues that ought to be fixed.
The initial entries are things I noticed while experimenting with
perm_invent; there is lots of older stuff that could/should be
there too. I'm not sure whether the first one is OSX-specific; the
others aren't.